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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

39057 results found.

  1. GRB 241107A: INTEGRAL IBIS localization
  2. GRB 241112A: Fermi GBM Final Real-time Localization
  3. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  4. IPN triangulation of GRB 241107A (short/hard)
  5. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  6. GRB 241025C: VZLUSAT-2 detection
  7. GRB 241025A: VZLUSAT-2 detection
  8. GRB 241018A: cubesat Avion detection
  9. Fermi trigger No 752990530: Global MASTER-Net observations report
  10. GRB 241111A: Fermi GBM Final Real-time Localization
  11. GRB 241030B: TESS detection of optical counterpart
  12. Fermi trigger No 752878030: Global MASTER-Net observations report
  13. Integral GRB241109.89: Global MASTER-Net observations report
  14. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  15. EP241107a: AbAO optical upper limit
  16. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  17. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  18. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  19. GRB 241108A: Swift-XRT observations
  20. EP241107A: MASTER optical observations of xray transient
  21. EP241107a: KAIT optical observations
  22. GRB 241108A: Swift ToO observations
  23. GRB 241030A: TESS observations
  24. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  25. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  26. GRB 241025A: radio detection with the VLA
  27. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  28. EP241107a: GSP detects optical counterpart
  29. GRB 241107A: SVOM/GRM detection of a short burst
  30. GRB 241105A: EP-FXT follow-up observations
  31. GRB 241105A: SVOM/GRM observation
  32. GRB 241105a: PRIME near-infrared upper limits
  33. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  34. EP241107a: GIT optical observations
  35. EP241107a: Global MASTER-Net observations report
  36. EP241107a: SVOM/C-GFT optical observations
  37. GRB 241025A: LBT optical observations
  38. GRB241105A: Gemini-South Optical Afterglow Detection
  39. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  40. GRB 241105A: Swift/UVOT Detection
  41. EP241101a: CrAO ZTSH optical observations
  42. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  43. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  44. GRB 241105A: BOOTES-7 optical detection
  45. GRB 241030A: Mondy optical observations
  46. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  47. Konus-Wind detection of GRB 241105A (short with extended emission)
  48. Konus-Wind detection of GRB 241021A
  49. GRB 241105A: SVOM/VT optical afterglow observations
  50. GRB 241105A: Swift-XRT afterglow detection
  51. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  52. GRB 241104A: Swift-XRT observations
  53. GRB 240511A: LCO upper limits
  54. GRB 241104A: Fermi GBM Observation
  55. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  56. GRB 241105A: Swift ToO observations
  57. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  58. GRB 241104A: Swift ToO observations
  59. GRB 241104A: NOT optical non-detection
  60. GRB 241105A: GOTO tentative optical counterpart candidate
  61. Fermi GRB 241105A: Global MASTER-Net observations report
  62. GRB 241104A: SVOM/VT optical candidate
  63. GRB 241105A: Fermi GBM Final Real-time Localization
  64. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  65. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  66. GRB 241104A: SVOM/GRM observation
  67. EP241104a: EP detection of GRB 241104A X-ray emission
  68. GRB 241010A: host galaxy redshift z = 0.977
  69. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  70. GRB 240821A: further radio observations with the VLA
  71. Fermi GRB 241104A: Global MASTER-Net observations report
  72. GRB 241104A: Fermi GBM Final Real-time Localization
  73. GRB 241030A: GRBAlpha detection
  74. EP241103a: GIT optical upper limit
  75. Fermi trigger No 752365806: Global MASTER-Net observations report
  76. EP241101a: Optical upper limits with Kinder observations
  77. EP241101a: OHP/T193 optical observations
  78. EP241103a: EP observation update
  79. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  80. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  81. EP241103a: GSP optical upper limit
  82. EP241103A: LCO optical observations
  83. EP241103a: Global MASTER-Net observations report
  84. GRB 241030A: Rapid release of TESS data.
  85. EP241101a: Global MASTER-Net observations report
  86. GRB 241029A: GRBAlpha detection
  87. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  88. Swift GRB 241101A: Global MASTER-Net observations report
  89. GRB 241101A: FRAM-ORM optical limit
  90. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  91. EP241021a: Upper limit from Konus-Wind observations
  92. GRB 241101A: Swift-BAT refined analysis
  93. GRB 241030A: further SAO RAS optical observations
  94. GRB 241030A: Optical Observations via Virtual Telescope Project
  95. GRB 241030B: Swift-XRT refined Analysis
  96. GRB 241026A: SAO RAS optical observations
  97. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  98. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  99. GRB 241101A: Swift detection of a burst
  100. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)

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